A further dimension of the frame (chassis) is the wheelbase. In contrast to the motor car, the wheelbase of a bike is very a dynamic value, through the construction of the front- and rear suspension it is largely dependent e.g., on the weight. Here again, it is different from the motor car, where the pay load, at the most, and then actually, only in exceptional cases, makes up half the tare-weight. The motorcycle constructor not only has to calculate a comparitively high pay load, he also has to make allowance for it's possible shifting by hard braking and/or acceleration.

What we're dealing with here, is the distribution of the wheel-loads. Thus, the center of gravity in a normal motor cycle may lie between the wheels, slightly to the rear of the middle, when braking however, it is shifted way to the front. It's even possible that the amount of fuel in the tank plays a minor role (in racing machines, a decisive role), even though it lies quite close to the center of gravity. A very important factor however, is the hard- or softness of the front springs. Diving is not only a problem as far as comfort is concerned, it can also influence the overall safety.

The steering cannot in fact, cope very well with too much or too little weight. Too much weight means that the steering is heavy and that the bike becomes difficult to handle, too little causes a total insensitivity. In this case, hard sprung racing machines have an advantage over, e.g., motor-cross bikes with their excessively long spring travel. Apart from that, racing machines are built exclusively to accommodate just the rider, in contrast to the average road-bikes.

A fascinating aspect is the ratio of an approx. 80 kg. rider to his, roughly 200 kg. superbike, this can be observed at any motorcyle-GP. The riders not only sit up straighter when braking, also their heart-stopping acrobatics when cornering are amazing. One can easily understand why, in the competition sector, the bikes are set up for one particular rider and e.g., as it is in long distance motor car racing, not just any pilot can race well with any randomly chosen vehicle. Something to think about are the light motorcycles weighing 60- 80 kg., that carry two people!

As we have already ascertained, higher velocity helps to attain stability. A lot of riders consider particularly fast riding as actually, quite simple, because (in theory) hard turning of the handle bars at high speed would seem impossible. However, the faster one travels, the more like a tunnel the (hopefully empty!) motorway becomes and, depending on the efficiency of the fairing (should the bike have one), the more the head-wind batters the rider. The only way to bring some sort of normality back, is to reduce speed. 06/12